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Pregnancy Weight Gain

Healthy weight gain range based on your pre-pregnancy BMI.

Short answer

The Institute of Medicine recommends 11.5–16 kg for normal-weight singleton pregnancies. Underweight women should gain more, those with higher BMIs less.

About you

Pre-pregnancy weight (kg)

Height (cm)

Current week of pregnancy

Current weight (kg) — optional

Twin pregnancy

Fill in the fields above to see your result instantly.

How it works

Institute of Medicine 2009 guidelines categorise total recommended gain by pre-pregnancy BMI. First trimester adds ~0.5-2 kg; later trimesters add ~0.4 kg/week.

Worked example

Pre-pregnancy BMI 22 (normal), 20 weeks: target total 11.5-16 kg, expected so far ~5-9 kg.

Who should use this

•Pregnant women tracking healthy gain
•Partners supporting pregnancy

Common mistakes

×'Eating for two' — only ~340 kcal extra in 2nd trimester, ~450 in 3rd
×Comparing with other pregnancies — every body is different

Frequently asked questions

Is gaining too much weight harmful?▾

Excessive gain raises gestational diabetes, hypertension and delivery complication risk. Discuss with your midwife.

Related calculators

Pregnancy Due Date →BMI Calculator →